In general, a laminated core manufactured by laminating and integrating laminar members is used as a rotor or a stator of a generator or a motor and, as methods of manufacturing laminated cores, i.e., by laminating the laminar members and then integrally fixing the laminar members, a tap fixing method using interlock taps, a fixing method using welding, for example, laser welding, a rivet fixing method, etc. have been known.
The tap fixing method is disclosed as manufacturing technology of a laminated core member in Patent Documents, i.e., Korean Patent Laid-open Publication Nos. 10-2008-0067426 and 10-2008-0067428. In manufacture of the laminated core member using such a method, iron loss occurs, particularly, it is difficult to execute embossing due to thickness reduction in a material, i.e., a steel sheet, and thus it is limited as technology for manufacturing laminated cores. The above-described Patent Documents and Patent Documents which will be described later disclose various kinds and shapes of laminated core members.
Recently, an adhesion fixing method, in which laminar members forming a laminated core member are adhered to each other by an adhesive so as to be integrated, has been proposed. Such an adhesion fixing method is disclosed in Korean Patent Laid-open Publication No. 10-1996-0003021 and Japanese Patent Laid-open Publication No. H5-304037.
With reference to Japanese Patent Laid-open Publication No. H5-304037 Among the above-described Patent Documents, a material for manufacturing a motor core, i.e., a steel sheet, is fed to a first press die and a second press die by a feed roller and, before the steel sheet is supplied to the first press die, an adhesive is applied to the surface of the steel sheet by an application roller and a nozzle.
Further, blanked members (laminar members) sequentially accumulated in the first press die and the second press die due to blanking of the material are integrated by the adhesive, thereby manufacturing an adhesive laminated core.
The above-described adhesion fixing methods, i.e., the adhesive laminated core manufacturing method, may reduce manufacturing costs, as compared to the laser welding method, and correspond to thickness reduction in the steel sheet. But, since the laminar members are integrated by a resistance heater, fast and uniform hardening of the adhesive is difficult and breaking of the heater may happen. Further, the core members passing through the heater and peripheral parts of the heater, for example, parts forming the dies may be thermally deformed (thermally expanded) or damaged, misalignment of the core strips and a defective product may occur due to lowering (change) of straightness/accuracy of a region (the laminating barrel), through which a product, i.e., the core members, passes, and product quality may not be uniformly maintained. Further, since elements, such as the press dies, the nozzles, the application roller, etc., are separately provided and independently operated, precise control for applying of the adhesive and blanking of the material is required.
Further, in a conventional adhesive laminated core manufacturing apparatus, an outlet of a nozzle to apply an adhesive may cause leakage of the adhesive or pollution around the outlet, the adhesive leaked from the nozzle may be adhered to the surface of the nozzle and thus cause clogging of the outlet of the nozzle and pollution. These problems may disturb precise application of a fixed quantity of the adhesive and reduction in the hardening time.
Moreover, the conventional adhesive laminated core manufacturing apparatus has a difficulty in applying a regular amount of the adhesive to the surface of a steel sheet each designated cycle, and requires precise management of the adhesive supply pressure, i.e., the pressure of the adhesive within the nozzle, so as to accurately control the discharge quantity of the adhesive and the operation time of the nozzle (application timing of the adhesive), and, if an adhesive application process is not effectively executed, delamination of the laminated core occurs and causes a defective product and, thus, productivity may be lowered due to increase in a defect rate and management costs may be increased.